A.A. Мaksimov1, S.F. Gorgadze2

1,2 Moscow Technical University of Communications and Informatics (MTUCI) (Moscow, Russia)

1 a.a.maksimov@mtuci.ru; 2 s.f.gorgadze@mtuci.ru

Formulation of the problem. Linearization of the radio frequency path for amplifying signals with amplitude and phase modulation in digital communication channels in order to meet the requirements for the level of out-of-band emissions and increase the speed of information transmission is inevitably accompanied by a decrease in its energy efficiency.

Goal of the work. Consideration of aspects of linearization of power amplifiers with energy-efficient options for their construction in terms of the achievable linearity of amplification of signals with amplitude and phase modulation, based on the electrical equivalent circuit of the active element.

Results of the work. A method has been developed for calculating the operator of inertia-free nonlinear signal transformations with amplitude and phase modulation in a power amplifier based on its electrical equivalent circuit to study a wide range of its operating modes with the absence or presence of separate amplification and regulation by supply voltage under a resonant or broadband load. Amplification options were considered with linear regulation of the power amplifier supply voltage and its operation in boundary and under voltage modes, as well as with separate amplification of the high-frequency component and amplitude envelope of the signal with restoration of the latter in overstressed operating modes, as well as in the key class D mode. It has been established that in the latter case there are easily compensated, but significant amplitude and phase distortions of the signal, but only at a low level of its amplitude, not exceeding (20-25)% of its maximum permissible value, which is specified in article; When the signal amplitude level increases, up to the maximum permissible, nonlinear distortions are practically absent. In the remaining cases considered, in addition to restoring the amplitude envelope of the signal in the overvoltage mode of operation of the power amplifier, it is possible to almost completely compensate for nonlinear distortions of the signal with similar final values of the characteristics of residual nonlinear distortions and with an output useful power of the amplifier of (32-36)% greater than in the case of restoring the signal amplitude based on regulation by the supply voltage in combination with its key operating mode. When regulating the supply voltage in combination with restoring the amplitude envelope of the signal in the amplifier in the overvoltage mode of its operation, it was not possible to compensate for nonlinear distortions of the signal when its amplitude level at the input exceeded approximately 0.8 of the maximum permissible. This problem can be solved by reducing the amplitude of the input signal, as a result of which the output power of the amplifier after linearization decreases by approximately (60-64)% compared to the absence of regulation. Therefore, in this case, it is advisable to use combined amplification using at least two amplification stages in combination with their linearization.

Practical significance. The results of the work can be used in the development of linear energy-efficient radio paths for amplifying complex composite signals with amplitude and phase modulation of digital information transmission channels of promising radio systems.

Мaksimov A.A., Gorgadze S.F. Linearization of a power amplifier with separate by strengthening and regulating the mode according to supply voltage. Radiotekhnika. 2025. V. 89. № 1. P. 5−23. DOI: https://doi.org/10.18127/j00338486-202501-01 (In Russian)

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